Several techniques exist in the field of spinal surgery for reducing a spinal rod into a posterior pedicle screw. The primary technique utilizes a separate rod reduction instrument that couples to the head of the screw after the screw is inserted and the rod is placed, such as rocker forks or ratchet style instruments, which are designed to reduce the rod one level at a time, i.e., to each pedicle screw separately. Such segmental reduction techniques may produce large axial loads on the pedicle screws.
Alternatively, a rod can be conformed to a specific deformity and then seated within an implanted pedicle screw. Once seated, the deformity can be corrected by bending the rod in situ. This technique may be time-consuming and places stresses and strains on the rod prior to implantation.
Certain rod reduction techniques utilize specialty reduction pedicle screws that include integrated upwardly extending tabs that can be used to reduce the rod gradually over the entire length of a deformity. Once the rod reduction is completed, the extended tabs are broken off. This technique, however, is typically limited to the reduction screw only and can cause the implant to be expensive.